The invention relates to a rock drilling machine that comprises a body, a percussion element arranged inside the body and, further, a drill shank, to which a tool may be attached for breaking rock. A percussion device comprises a percussion element that generates stress pulses through the shank to the tool. Further, the rock drilling machine comprises an axial bearing having one or more pressure medium-operated axial pistons, with which the shank may be pushed in the axial direction relative to the body a predefined travelling length toward the stroke direction. The impact surface of the shank may then be set at a required axial point for receiving stress pulses. The axial piston is operated by pressure medium, whereby it comprises a working pressure surface that is located in a working pressure space belonging to the axial bearing, to which the pressure of the pressure medium may be fed from a feed channel. A force may then be directed to the axial piston in the stroke direction.
Further, the invention relates to an axial bearing module of the rock drilling machine, which comprises one or more pressure medium-operated axial pistons.
The field of the invention is defined in more detail in the preambles of the independent claims of the patent application.
It is known to equip a rock drilling machine with an axial bearing, with which a drill shank belonging to the rock drilling machine may be moved to a planned impact point during drilling. The striking power may then be adjusted by adjusting the position of the drill shank. In addition, the axial bearing may be used to damp the stress pulses reflected back to the rock drilling machine from the rock. The axial bearing is typically positioned in an intermediate flange between the front body and back body of the rock drilling machine. A drawback with the known axial bearings is that their maintenance is complex and slow. Further, the assembly of the axial bearing and a possible later replacement of components is difficult. Yet another detected problem with axial bearing solutions is that the supporting forces caused by the operation of the axial bearing cause unnecessary strain on the structures of the rock drilling machine.